The present invention relates generally to dental appliances and restorations and more particularly to prefabricated components for use in dental appliances and restorations and methods of manufacture thereof.
Dental appliances and restorations such as bridges, crowns, dentures and the like may be used to restore a missing tooth and retain natural teeth in position and prevent migration subsequent to orthodontic treatment. Structural components used in these appliances often include wires, bars, posts, shells, beams, clasps and other shapes. The shape of the structural components may vary depending upon the requirements of the appliance.
The manufacture of frameworks for bridges using current techniques can be time consuming and labor intensive. Some techniques may involve taking uncured fiber-reinforced composite material and forming uncured strips of the fiber-reinforced composite material into a bridge framework upon a dental cast. The procedure can be an involved and complex process depending upon the final shape desired. Moreover, dental technicians and practitioners may use less than the optimum amount of fiber for reinforcement when preparing the dental framework in order to reduce the cost which may lead to low strength and therefore potential fracture of the final product. Furthermore, the complexity of the dental appliance may require a certain dexterity to achieve optimal properties that may not be achievable by some technicians and practitioners.
Other types of materials such as metals, alloys and ceramics have been used with great success in the manufacture of dental restorations and have exhibited flexural strengths as high as 300 MPa and above. Unfortunately, the aesthetic appearance is sometimes less than pleasing due to the unfavorable light transmission properties of these materials.
There remains a need to simplify the process of fabricating dental appliances to reduce time and labor involved in the preparation process and to provide appliances having optimum properties. It is desirable to reduce the risk of contamination during the fabrication of dental appliances. It is desirable to maintain strength of dental appliances without sacrificing aesthetic and light transmitting properties.
These and other objects and advantages are accomplished by the present invention wherein preshaped, prefabricated cured components are prepared in a variety of shapes and sizes to be used in the fabrication of dental appliances. Preferably the components are fabricated of a fiber-reinforced composite material comprising fibers impregnated with a polymeric matrix. After impregnation of a fibrous material with a polymeric matrix, the resultant fiber-reinforced composite material is shaped and is partially or fully cured to the point of sufficient hardness to provide a component for use in the fabrication of dental appliances including but not limited to orthodontic retainers, bridges, space maintainers, tooth replacement appliances, dentures, crowns, posts, jackets, inlays, onlays, facings, veneers, facets, implants, abutments and splints.
In one embodiment of the present invention, the components are in the shape of a structure for immediate use in the fabrication of a dental appliance. The structural components are formed into any known shapes useful in the fabrication of a dental appliance or restoration. Preferably, the structural components are in the shape of bars or pontics. The pontics have interproximal extensions and may be single unit or multiple unit useful in the fabrication of frameworks for bridges. The structural components may be xe2x80x9cready-to-usexe2x80x9d for immediate use in the fabrication of a dental appliance or restoration or may be further modified, for example by cutting, carving or grinding prior to using in the fabrication of a dental appliance or restoration.
In another embodiment of the present invention, the components are formed into pieces or blocks of fiber-reinforced composite material. The blocks of material are useful in making a variety of shapes and sizes and may be modified by a variety of methods including but not limited to machining, carving, cutting, grinding, etching and abrading.
The bars, pontics and blocks may be of any cross-sectional configuration effective to provide strength and stiffness to the finished dental appliance.
In yet another embodiment herein, blocks of particulate filled composite material are formed and may be provided in a variety of shapes and sizes. The particulate filled composite blocks may be modified by a variety of methods including but not limited to machining, carving, cutting, grinding, etching and abrading. The blocks may be of any cross-sectional configuration effective to design or model dental materials and restorations therefrom.
In the method of the present invention, the components are made after the impregnation of the fibers with a polymeric matrix. After impregnation of the fibers, the resultant composite material is formed into, for example, a long bar and cured or polymerized to a hardness whereby the bar may be cut and/or machined without deforming the structural integrity of the bar. The bar is preferably cut into short segments and is ready for use in the fabrication of dental appliances. The bars may be used as is or may be further modified by cutting, grinding, machining, and the like to provide a specifically shaped or customized component. The component may further be veneered with particulate-filled composite to develop clinically acceptable anatomy.